Reactions of Norwegian children with severe egg allergy to an egg-containing influenza A (H1N1) vaccine: a retrospective audit

Bård Anders Forsdahl

Department of Pediatrics, University Hospital of North Norway, Tromsø, Norway

Correspondence to Dr Bård Anders Forsdahl; forsdahl{at}c2i.net

Abstract

Design Retrospective audit.

Setting Secondary paediatric outpatient clinic, Tromsø, Norway.

Participants The participants were 80 (62.5% boys and 37.5% girls) children and adolescents with a diagnosed egg allergy who had to be on an egg-free diet and be unable to eat any food containing any amount of egg, including egg-containing baked goods, without an allergic reaction to egg protein. We also included patients who were sensitised to egg but had never been exposed to egg or egg-containing baked goods and were on an egg-free diet. Other atopic diseases among the study participants were also registered.

Intervention The vaccination took place from November to December 2009. The patients were vaccinated with a monovalent influenza A (H1N1) vaccine that had an ovalbumin content <0.33 μg/ml. They were divided into two groups, receiving the vaccine either as a single dose or as a fractionated dose. Patients were selected for the fractionated dose because of their prior reaction to egg or because they never had been exposed to egg.

Primary outcome There were no serious adverse reactions to the vaccine; only one mild adverse reaction and two possible adverse reactions.

Results Patients ranged in age from 10 months to 16.5 years. Thirty-eight (48%) patients received a fractionated dose. Sixty-three (79%) had one or more atopic disease apart from egg allergy. With regard to atopy, serum specific IgE levels or skin prick test, there were no significant differences between the groups receiving the vaccine as a fractionated or as a single dose.

Conclusions The study confirmed that patients allergic to egg can be safely vaccinated with a regular influenza vaccine containing <0.333 μg/ml ovalbumin, even if these patients had displayed previous anaphylactic reactions to egg and had been diagnosed with concurrent atopic diseases.

Footnotes

To cite: Forsdahl BA. Reactions of Norwegian children with severe egg allergy to an egg-containing influenza A (H1N1) vaccine: a retrospective audit. BMJ Open 2012;2:e000186. doi:10.1136/bmjopen-2011-000186

Funding There is no study sponsor, and BAF has received no funding for this manuscript.

Competing interests BAF has completed the Unified Competing Interest form and declared that he has no relationship with any company for the submitted work. BAF has no relationship with any company that might have an interest in the submitted work in the previous 3 years. The wife of BAF, partners or children has no financial relationships that may be relevant to the submitted work. BAF has no non-financial interest that may be relevant to the submitted work.

Ethics approval We obtained the written consent of the parents of the case histories presented in this article. We did not obtain approval for the study from the Regional Committee for Research Ethics in Northern Norway before commencing the vaccination drive, but we applied for approval in November 2010. The Committee responded that it considered the vaccination drive as ‘part of ordinary treatment’, even though it could have been experimental and that the project therefore fell outside its mandate. However, it added that we as the applicants had the right to ‘publish the treatment’.

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.